Printed in Great Britain. 0 1987 Pergamon Journals Ltd. The polar tensors, effective charges and separation ratios of over- lapped bands in methanes

Abstract-The separation ratios for the overlapped bands of CH3D, CD,H and CH2D2 molecules have been obtained by a method based on the differences in molecular and electronic symmetry point groups. The signs of all the aP/aQi elements are established. Also, the atomic polar tensors and effective charges are calculated using the intensities of all five CH,D4 _ x molecules